You might try Maison Intenationale de la Jeunesse et des Etudiants(www.mije.com). They have 3 nice hostels. Le Village Hostel is nice, too (www.villagehostel.fr).
I would try some of the budget hotels. Hostels have upped their prices tremendously and sometimes are no more bargain (ok doesn't mean that is the case for all of them). If you search for places in the double digit arrondisement you might get some pretty good deals. I know two I have tried before. http://www.armstrong-paris-hotel.com/ http://annexe-paris-hotel.com/